metan

Submitted by danijela on Tue, 06/03/2014 - 13:41
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koliko grama metana mora da se sagori da bi se dobilo 2,0MJ toplote? delta rH(CO2)= -394kJ/mol                     deltafH (H2O)= -286kJ/mol   deltaHf(CH4)= -76kJ/mol    resenje 36 hvala

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milicaradenkovic - Tue, 06/03/2014 - 20:33

CH4+2O2---------------->CO2+2H2O

deltaH(O2)=0 kJ

deltaH=deltaH(CO2)+2*deltaH(H2O)-deltaH(CH4)-2*deltaH(O2)

deltaH= -394+2*(-286)-2*0-(-76)= -890 kJ

n=Q/deltaH=2*1000/890=2.25 mol

m(CH4)=n*Mr=2.25*16=36 g